Background. Despite nearly 30 years of the HIV epidemic in the U.S., HIV incidence and prevalence continues to grow. Men who have sex with men (MSM) are, by far, the population most affected, as they make up the majority of new infections and the majority of individuals living with HIV in the U.S. The prevalence of HIV among MSM is estimated at an alarming 19% domestically (CDC 2010), rates comparable to endemic settings in certain regions of sub-Saharan Africa where approximately 20% of the adult population is HIV- infected. Study after study has demonstrated a staggeringly high prevalence of childhood sexual abuse (CSA) in MSM, and study after study has shown an association of CSA to HIV risk in MSM. A successful intervention for MSM with a CSA history to prevent HIV has the potential to avert infections among some of the riskiest members of the most HIV vulnerable group in the U.S. Design. This two-arm RCT is to test the efficacy of a psycho-social intervention that addresses intersecting epidemics among MSM: HIV and CSA. It follows directly from our successful r34 in which the integrated intervention was developed and piloted in a mini, randomized study. The experimental condition integrates sexual risk reduction counseling with Cognitive Processing Therapy for Sexual Risk (CPT-SR). CPT-SR has been specifically piloted on MSM with CSA histories and sexual risk to reduce interfering negative CSA-related thoughts about self, to more accurately appraise sexual risk, and to decrease avoidance of sexual safety considerations, and through rehearsals of sexual safety behaviors. The active and time-matched comparison condition is risk reduction counseling plus supportive psychotherapy. We will randomize HIV-uninfected MSM who report a history of CSA and multiple recent sexual risk episodes for HIV (unprotected anal/vaginal intercourse) across two sites (Boston and Miami). The primary outcome will be self-reported sexual risk taking as assessed via ACASI. Secondary outcomes include CSA-related trauma symptom severity, and CSA-trauma related cognitions (perceived HIV risk, negative thoughts about self, self -efficacy) and behaviors (avoidant coping substance use, dissociation). Reductions in incident STIs will be an exploratory outcome. Trauma characteristics and demographics will be examined as moderators of the treatment effect and secondary outcomes will be examined as mediators of the treatment effect on sexual risk. Study assessment points are at baseline, 3 (post treatment), 6, 9, and 12-month follow-ups. Efficacy testing in community settings, with master level clinicians, using short term therapy are design features to support community uptake and sustainability. Innovation. The use of cognitive-behavioral technologies to address mental health issues that interfere with the sexual safety of MSM is an innovative application, theoretically designed to increase the modest efficacy of previous prevention work. This innovation also supports the mental and physical health of MSM more broadly, and may be a model for addressing other HIV prevention targets impacted by interfering mental health issues.